Concentric shell type hot-air heater



y 1951 R. J. BOYER 2,553,168

CONCENTRIC SHELL TYPE HOT AIR HEATER Filed NOV. 4, 1947 2 Sheets-Sheet l I N V EN TOR. fiard f 961 May 15, 1951 R. J. BOYER CONCENTRIC SHELL TYPE HOT AIR HEATER 2 Sheets-Sheet 2 Filed NOV. 4, 1947 Patented May 15, 1951 CONCENTRIO'SHELL' TYPE HOT-AIR HEATER Ric ard J Bo r, Hayward, Minn.-

Application November 4, 1947, SerialNo, 783,975:

This invention relates to a heater designed speoially for use with grain or other products that are stored in silos, bins, cribs or the like. It. relatively small, also portable, and when not in use, may easily be stored away under cover.

For its objects the present heater aims to de= liver a large volume of heated air, with the aid of a blower, to the confined space in which the to-be-dried products are contained; and to pro-. vide such a construction which is simple, coma pact, and inexpensive. These and other objects of my invention, as will hereinafter appear, may be realized from a construction such as is exemplified in the accompanying drawings wherein-f Figure 1 is a view in side elevation of the heater in its entirety;

Fig. 2 is a central vertical section through the heater;

Figs. 3 and 4 are transverse sections taken, re: spectively, on lines 3--3 and laiof Fig. 2;

Fig. 5 is a transverse section, taken on line 5175 of Fig. 1;

Fig. 6 is a transverse section, taken on line e t of Fig. 2; and

Fig. 7 is a detail, partly in elevation and partly in section, of a carburetor having certain features of advantage when used with the burner for the present heater.

As shown best in Figs. 1 and 2, the heater'comprises a cylindrical casing A having an end wall ID at the front. This casing may be suitably braced, as by a supporting framework, which comprises legs 12 upstanding from base rails 54. Concentric withthe casing A and disposed therewithin but spaced therefrom is an outer shell B extending from a rear wall I5 forwardly to a point short of the front wall where a large transverse passageway :1: is provided. An annular passageway a extends'between the casing and outer shell for the length of the heater.

Arranged within the outer shell B in its bottom portion is a longitudinally extending fur nace comprising a cylindrical tube 28 having a refractory lining 2| on its interior. The furnace is of greater diameter than the width of the space between the inner and outer shells and extends partially into the space between the outer shell and the casing and also between the inner shell and the drum D to increase its heating effect. This furnace, which opens out at the front of the heater, extends to its back wall [5 adjacent which it is provided with wide openings 25 on opposite sides (see Fig. 3) which communicate with an annular passageway b that extends forwardly from the rear wall [5. This annular passageway 6 Claims. (01. 12:6106) 2' is defined in part by-an inner shell .0 which is spaced from-and intermediatel-y. of the outer shell B and an inner drum D. The inner shell C ex: tends from theback wall I5 forwardly to join with an annular wall 26 which is spaced from the front Wall Ii], paralleltherewith, and joinedto the outer shell B to form-a frontwall for the an, nular passageway bbetween the two shells B and C. Between theshellC anddrum D is an..- other annular passageway c through-which near one end-is extendeda vertical duo-t Bil-to estallish communication therebetween- (see Fig. i), and at its other end aflue pipeS-Z whichcontinues through the shells G and-Band-casingA,

for delivery of products of combustion to theatmosphere. Inlet openings 35 are provided through the casing A at desired-points, desirably-at the rear end of'the heater.

The rear -walll5 is provided with-a large-central opening it-registering with a similar open.- ing Win the adjacent wall 45-of a cylindrical housing wherein is a blower it: mounted to rotate witha shaft 50 whereon it is supported. This'shaft is journaled for rotation-within suit able bearings carried by the housing wall ifiand by an opposite wall5'5 of-the-same housing. Ex teriorly ofthe blower housing the shaft EU-car ries one ormore-pulleys 56- over which may be trained a belt 58 driven by-a pulley tfiattached to the shaft Bl ofa motor uni-t M.

At or within==the open end of the-furnace provided-by the tubular wall Zilis positioned a. jet nozzle affixed to the end-0f a burner pipe 68 through which oil or fluid-fuel is delivered from-a fuel pipe 6'! in connection with an elevatedsupply tank 10. As shown best in Fig. "I, the-burner comprises. a float chamber 72 interposed in the fuel line 61; together with an air-control'theree for. This control may consist of a pipe lia leading to asupply source (not shown) where a-i-r ismainta-ined under pressure, a pressure guage being connected intothe air lineto afford a visual indication of the pressure conditions; arelief valve 18'alsotapped intothe 'lineto providefor relief of air in excess of the desired pressure; also a valve-comprising a chambered body at havinga seat 8:] with which'a' disk 82 coacts to open or close a passageway between the airline "l5 and the burner pipe 6.6; the disc is carried-at one end of a stem 84 which is pi-votall'y connected-at 86 to -a 'bel-l cran-k tlfl one of whose arms is pivotally mounted at 85 upon an elbow-til which extends lateral-lyf rom the valve 'bodyte join with the air pipe *15, the other arm of the bell crank being engaged-by a wing n-ut Q I which is free to travel.

is adjustably secured to a threaded stem 93 upstanding from the pipe 15 to traverse the bell crank arm thereabove. A spring 94 surrounding this stem exerts an upward pressure against the bell crank arm such as to rock the bell crank toward the valve and normally hold its disc toward the seat therefor, but spaced away therefrom the minimum distance that may be determined by adjustment of the wing nut 9|. Obviously this adjustment is subject to change, as conditions require, so that the proportion of air passing through into the burner will be varied.

In operation, a hot flame Will be projected from the nozzle near the open end of the furnace. Through the carburetor the needed amount of air is supplied for effective mixture with the fuel which is atomized when issuing through the jets of the nozzle. The flames thus filling the furnace will quickly produce a high degree of heat in the surrounding space. At the far end of the furnace the heated air, together with products of combustion, escapes through the lateral openings 25 into the annular passageway b where it travels upwardly and forwardly around opposite sides of the inner shell C toward the top of the passageway. Continuing, the heated products of combustion are drawn downwardly through the duct 39 into the central chamber d within the inner drum D, from whence they pass out through the vertical flue 32 into the atmosphere. It will be noted that the intensely heated air originating in the furnace moves out at the rear end, then upwardly along opposite sides of the inner shell C along whose length it The passageways thus provided for travel of the flames and the products of combustion lie intermediately of other passageways into which fresh air is led through the inlets 35, starting at the rear end of the outermost annular passageway a. and moving freely toward the front end thereof where communication is established with the innermost annular passageway c which also lies between the heated inner shell C and drum D. Through this latter passageway the air advances rearwardly toward the outlet opening 40 and into the inlet opening 42 of the blower housing. From this point the air is forcibly sent on its way through a duct 62 which leads to a crib, silo, bin, or other container for the to-be-dried products.

7 The several shells and inner drum are mutually supported, as required, by intermediate bracing as suggested in Figs. ,4 and 6. For this purpose the inner drum D is maintained in fixed spaced relation with the inner shell C as by a plurality of struts 36 and also the duct .30. The inner shell C is supported at opposite ends by the vertical walls which connect it with the outer shell B, the latter being maintained in, a fixed spaced relation with the casing A as by strap brackets 31 with each of which is associated an adjusting screw 38. In like manner the tubular furnace may also be supported in a fixed position with the aid of brackets 38 each having an adjusting screw 39.

The heater of my invention is exceedingly effective for its intended purpose. This is so largely because of the arrangement of intercommunicating passageways through which the heated products of combustion are passed, and

other passageways which are adjacent thereto through which the incoming air travels to be high heated by the adjacent walls. The air movement proceeds first in the outside passageway a, 1 lg from the rear to the front. During this 4 portion of the travel there is a transfer of heat through the outer shell B. The air then moves transversely of the outer shell B into the annular passageway 0. Here the air is subjected to delivery of heat from the inner shell C and the inner drum D. The movement of the air in this last stage is from front to rear. By the time the air has completed its tortuous passage it has arrived opposite the blower by which it is impelled with heavy force outwardly on its way through the delivery duct.

I claim:

1. A dryer of the kind described in which is 7 combined an elongated enclosing cylindrical casing with an inlet opening near one end and with opposite end walls in one of which, proximate to the inlet opening, is an outlet opening, an outer concentric shell aflixed within the casing in spaced relation thereto and extending from one end wall to a point short of the opposite end wall, an inner concentric shell aifixed within the outer concentric shell in spaced relation thereto and coextensive therewith, an annular wall interconnecting the two shells at a point adjacent to but spaced from the other end wall of the casing, an inner drum afilxed within the inner concentric shell in spaced relation thereto and to the end walls of the casing; a duct interconnecting the space between said shells and said inner drum, a flue pipe extending from the inner drum through the shells and casing to the atmosphere, a furnace extending lengthwise of the casing between the outer and intermediate shells and in communication with the annular space therebetween at the casing end proximate to the air inlet whereby the products of combustion from the furnace are free to travel around and lengthwise of said annular space to and through the duct and, thence for escape therefrom into the atmosphere, the air entering through the inlet being free to travel around the outermost annular space from one end of the casing to the other adjacent the heated outer shell and thence inwardly to the innermost annular space and lengthwise of the casing in the opposite direction between the heated inner shell and inner drum to be raised in temperature thereby prior to eduction through the outlet opening at the casing end proximate to that where the inlet opening is located.

2. A heater of the kind described comprising an elongated horizontal casing, inner and outer shells arranged within the casing, said casing and shells being spaced apart substantially uniformly from end to end, a horizontal furnace extending between the bottom portions of the inner and outer shells and having an opening at its rear end providing communication with the space between said inner and outer shells, an inner horizontal drum located within the inner shell in spaced relation with the same, a vertical duct connecting the space between the inner and outer shells with the inner drum at the front portion thereof, and av vertical fiue connection extending from the rear portion of the inner drum to the atmosphere, there being means forming transverse passageway establishing communication between the space between the outer shell and the casing and the space between the inner shell and the drum, means forming an air inlet opening into the space between the outer shell and the casing located at the rear end thereof, and means forming an air outlet from the space between the inner shell and the drum located at the rear end of said last mentioned space whereby air is free to travel from the space between the outer shell and the casing to and through the space between the inner shell and the drum and the products of combustion are free to travel from the furnace to said flue through the space between the inner and outer shells and through the duct and the drum.

3. A heater of the kind described comprising an elongated horizontal casing, inner and outer shells arranged within the casing, said casing and shells being spaced apart substantially uniformly from end to end, a horizontal furnace extending between the bottom portions of the inner and oute shells and having an opening at its rear end providing communication with the space between said inner and outer shells, an inner horizontal drum located within the inner shell in spaced relation with the same, a vertical duct located at one end of the drum connecting the space between the inner and outer shells with the inner drum, and a vertical flue connection at the other end of the drum extending from the inner drum to the atmosphere, there being means forming a transverse passageway establishing communication between the space between the outer shell and the casing and the space between the inner shell and the drum, means forming an air inlet opening into the space between the outer shell and the casing located at the rear end thereof, and means forming an air outlet from the space between the inner shell and the drum located at the rear end of said last mentioned space whereby air is free to travel from the space between the outer shell and the casing to and through the space between the inner shell and the drum and the products of combustion are free to travel from the furnace to said flue through the space between the inner and outer shells and through the duct and the drum.

4. A heater according to claim 2 in which the furnace extends longitudinally of the casing throughout the length of the same and is of greater diameter than the space between the inner and outer shells and protrudes partially into the space between the casing and the outer shell and into the space between the inner shell and the drum.

5. A heater of the kind described comprising an elongated horizontal casing, inner and outer shells arranged within the casing, said casing and shells being spaced apart substantially uniformly from end to end, a horizontal furnace extending between the bottom portions of the inner and outer shells and having an opening at its rear end providing communication with the space between said inner and outer shells, an inner horizontal drum located within the inner shell in spaced relation with the same, a vertical duct connecting the space between the inner and outer shells with the inner drum at the front end thereof, a vertical flue connection extending from the rear portion of the inner drum to the atmosphere, there being means forming a transverse passageway establishing communication between the space between the outer shell and the casing and the space between the inner shell and the drum, means forming an airinlet opening into the space between the outer shell and the easing located at the rear end thereof, and means forming an air outlet from the space between the inner shell and the drum located at the rear end of said last mentioned space whereby air is free to travel from the space between the outer shell and the casing to and through the space between the inner shell and the drum and the products of combustion are free to travel from the furnace to said flue through the space between the inner and outer shells and through the duct and the drum, a blower housing affixed to the rear end of the casing and of approximately the diameter of the same and having an inlet opening in register with the outlet opening of the casing, whereby to receive heated air flowing therefrom, and blower means within the housing for forcibly discharging the air therefrom.

6. A heater according to claim 2 in which the spacing between the casing and the outer shell is smaller than the space between the inner shell and the drum.

RICHARD J. BOYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 4,637 Loveland July 14, 1846 2,015,195 Sadwith Sept. 24, 1935 2,172,399 Mueller Sept. 12, 1939 2,408,691 Shaw Oct. 1, 1946 

